It is commonplace to install metal flashing where a wall intersects the roof plane. In sloped roofing applications, it is typical for the roof to encounter a wall, such as a dormer. In flat roof installations, many roof systems terminate at a parapet, roof protrusion, or wall.
The roofing industry has typically frowned on second layer roof applications, due to the inability of the next cover roofing system to tie into existing flashing when encountering a wall. The problem is further exacerbated when a wall cover material, such as stucco, siding, or other wall cover, extends over the top edge of the existing wall flashing. To replace the existing wall flashing, the wall cover material needs to be removed and reinstalled or replaced. These steps add time and expense to roof replacement.
Despite the roofing industry's reservations regarding second layer roofing applications, the use and encouragement of second layer roof applications remains desirable, primarily due to cost and environmental impact benefits. Moreover, there is a substantial movement towards shingle recycling and keeping the existing shingles on the roof through another roofing cycle, as more communities come on board with shingle recycling efforts. Suffice it to say that, second layer applications are cleaner, while saving the owner money and the roofing contractor time.
What is needed, therefore, is flashing that can be used in second layer roofing applications that is able to tie into existing flashings when encountering a wall, without removal and/or replacement of the existing flashing.